Winding of yarn



March 19, 1968 B; K. JOHNSON WINDING OF YARN Filed March 2, 1965 INVENTO/P. BRYAN K. JOHNSON United States Patent Oflice 3,373,945 Patented Mar. 19, 1968 3,373,945 WINDING OF YARN Bryan K. Johnson, Ahergavenny, England, assignor to British Nylon Spinners Limited, Pontypool, England Filed Mar. 2, 1965, Ser. No. 436,664 Claims priority, application Great Britain, Mar. 11, 1964, 10,192/ 64 5 Claims. (Cl. 242-48) ABSTRACT OF THE DISCLOSURE Yarn is traversed to and fro along a rotating bobbin during the winding thereof on the bobbin with a cyclically varying traverse stroke. The length of yarn laid in one cycle of varying traverse strokes or in a low whole number multiple thereof is at least substantially equal to the length of yarn formed into a given textile article of required defined dimensions.

The invention concerns improvements in or relating to the winding of yarn.

Yarn, including within the meaning of that word continuous multifilament and monofilament structures, is usually wound on bobbins into so-called packages, for subsequent use in knitting, weaving and like textile processes.

Some of the most widely used yarn packages are those wound on a bobbin consisting of a cylindrical tube, the package having tapered, conically shaped end-portions. The tubes may be of metal, such as aluminum; or they may be of plastic material, usually in the form of slipsleeves fitting over metal cones.

The comically-shaped, tapered end-portions may be formed in a number of ways by variations in the length and/or speed of the yarn-traversing means employed to direct the yarn along the length of the bobbin. Thus, a conically-shaped taper may be formed by gradually and unidirectionally shifting the position of the end reversal point of the traverse stroke during the winding of the package; or a cyclical shifting of the end reversal point may be used instead. Further, a yarn package with comically-shaped tapered end-portions may have a bottom tapered end-portion formed in the former manner, and a top one formed in the latter manner. Such a yarn package is especially useful when the winding is carried out on a ring-twisting machine having a hydraulic builder unit, as it enables that machine to produce a true cone shape in both the tapered end-portions. The normal package in which nylon yarn is wound for knitting purposes is of the so-called pirn build, in which a constant traverse stroke is gradually shifted towards the top of the bobbin throughout the winding; but if that build is used on a ring-twisting machine having a hydraulic builder unit, the top tapered end-portion has a convex surface, not the desired straight one. This leads to an inferior weight per volume of yarn ratio. A multi-cycle variation in the position of the top end reversal point, however, enables a truly conical top tapered end-portion to be wound.

Apart from the above-mentioned advantage in connection with hydraulic builder units, the package build having a gradually and unidirectionally shifting bottom reversal point and a cyclically shifting top reversal point is of advantage in kitting performance, compared with the normal pirm build, as the existance of a layer of yarn along the entire length of the package at the inside thereof minimises the drag on the yarn when it is being taken off at the last stages of unwinding on the knitting machine. In a pirm build, the yarn being taken off from a nearly run-out package may be withdrawn in contact with quite a long length of the bottom surface, above the short constant traverse stroke of the initial layers; and such contact may impose a greater drag than contact with yarn itself.

Thus, package builds having one or both tapered endportions formed by cyclically varying, within the ambit of the end-portion, the position of the respective end reversal points of the traverse stroke are often used, and particularly is this so in the case of the package build having a cyclically varying top reversal position, and a unidirectionally varied bottom reversal position, of the traverse stroke, known as the composite pirn build, when such a package is wound on a ring-spindle machine with a hydraulic builder unit and is destined for use as a knitting supply package.

When yarn is withdrawn upwardly over the top end of double-taper yarn package in which at least the top tapered end-portion is formed by cyclically varying the position of the top end reversal point of the traverse stroke, the mean take-off tension Will vary cyclically in relation to the socalled pick cycle, that being the cycle of variation of the position of the reversal point of the traverse stroke.

The length of a panel of knitted fabric, such as a Womans stocking panel, is partly dependent on the mean take-off tension of the yarn supplied to the knitting machine. Hence, as the normal package build provides for the knitting of a number of stocking panels from thelength of yarn in one pick cycle and as the take-off tension varies in a cyclical manner directly proportionally to the variation in traverse strokes in that pick cycle, it is likely that the length of the given number of stocking panels will vary.

This is an undesirable situation, and one which is not met with in the case of the pirn build. That build is the one currently most used for stocking knitting, owing to the preponderance of ring-twisting machines having mechanical builder units which allow for the acceleration of the traverse motion and hence. for the formation of straightsided conical-shaped top tapered end-portion despite the gradual and unidirectional variation in the position of the top reversal point.

The ready acceptance of the composite pirn build for nylon continuous filament yarn is therefore somewhat dependent on the overcoming of the above-mentioned defect of stocking leg length variation; and the same is true, but to a lesser extent owing-to the comparative rarity of the build for stocking knitting, of the ordinary multicycle build in which both'tapered end-portions are formed by cyclical variation in the positions of the respective reversal points of the traverse.

The main object of the invention is the neutralisation of the stocking leg-length variation and like defects, arising when package builds of the types in question are used for knitting articles having a required standard length. The traverse/pick cycle ratio for two package builds included within the scope of the invention is diagrammatically illustrated in the accompanying drawing, in which:

FIGURE 1 is a projected plan view of a multicycle package build; and

FIGURE 2 is a projected plan view of a composite pirn package build.

Accordingly, in one aspect, the invention consists of a method of winding yarn in which the yarn is traversed to-and-fro along the length of a rotating bobbin. The method, as shown more clearly in FIGURE 1 of the drawing, comprises traversing the yarn 10 along a rotating bobbin 11, at least substantially throughout the period of winding, with a cyclically varying traverse stroke. The length of yarn laid down in one cycle of varying traverse strokes or in a low whole-number multiple thereof is at least substantially equal to the length of yarn to be formed into a given textile article of required defined dimensions.

The multicycle package build illustrated by the projected plan view in FIGURE 1 shows the reversal points for the traverse stroke rising and falling in phase. Two full traverses per pick cycle are shown.

By means of the invention, the complete cycle or cycles of tension variations, if any, will be constrained to occur within the exact confines of one textile article, such as the panel of a womans stocking; and thus difficulties of matching these articles for length or other dimension will not arise. Any variations in, for instance, the stitch size within the article will not be likely to be noticed.

Although generally the method of the invention will be carried-out by reference to one so-called pick cycle, it is within its scope to use a low whole-number, say 2 or 3, of such pick cycles to provide the desired length of yarn.

More specifically, the invention consists in a method of winding nylon continuous filament yarn to form a composite pirn package build 20, as hereinbefore defined, and as shown more clearly in FIGURE 2 of the drawing. The projected plan of the composite pirn package build 20 shows a cyclically varying top reversal position, and a unidirectionally varied bottom reversal position. Two full traverses are shown per pick cycle. Although the top taper is shown commencing with the traverse stroke at its longest, it is of course deemed understood by those skilled in the art that it is irrelevant to the invention whereabouts in the cycle the top reversal point is at the start of winding, so long as the length of yarn in the full cycle is related in the required manner to that of the given textile article. By way of example, the length of yarn laid down during one pick cycle of the top tapered end-portion is at least substantially equal to the length of yarn to be knitted therefrom in the panel of a womans stocking.

To carry out the method of the invention, it is necessary to fix the pick cycle to include such number of traverses of the yarn as will lead at least substantially to the total required length of yarn to be laid down in the pick cycle. For instance, in a composite pirn package wound for use as the supply of a stocking knitting machine, the length of nylon monofilament yarn in each traverse falls between 1500 and 2000 feet; and as the length of yarn knitted in the panel of a womans stocking is of the order of 4800 feet, the nearest approximation to this figure is obtained by including 3 traverses per single pick cycle.

Such a rate of picking is very much faster than normal. For instance, in the normal multicycle build the number of traverses per pick cycle is between about 30 and 50.

In general, it can be said that, with the size of bobbins now in use, the number of traverses per pick cycle is likely to fall between 2 and 5, when, for instance, nylon 15 denier monofilament yarn is wound with a multicycle or a composite pirn build on a draw-twister fitted with a hydraulic builder unit, and is destined for use in the panel of womens stockings.

Accordingly, the invention in another aspect consists in a yarn package wound on a bobbin with a cyclically .varying traverse strokes, the number of traverse strokes per cycle of varying strokes being between 2 and 5.

Although the invention has been described specifically with reference to nylon yarn and to the use of such yarn in the panel of Womens stockings, it is to be understood that it is not limited in scope to either such item. Yarns of polyester and isotactic polypropylene filaments may be usefully wound according to the invention, for instance.

What we claim is:

1. A method of winding yarn on a bobbin, comprising the steps of (a) traversing the yarn to-and-fro along the length of a rotating bobbin with a traverse strok which varies cyclically at least substantially throughout the winding; and

(b) cycling the variation of traverse stroke so as to provide a length of yarn per cycle, or low wholenumber mutilple thereof, that is at least substantially equal to the length of yarn to be formed into a given textile article of required defined dimensions.

2. Method according to claim 1, wherein the number of traverse strokes per cycle is between 2 and 5.

3. Method of winding yarn on a bobbin according to claim 1, wherein said traverse stroke having a bottom reversal point and a top reversal .point is cyclically varied by gradually shifting the bottom reversal point of the traverse stroke upwardly, and cyclically shifting the top reversal point of the traverse stroke upwardly and downwardly throughout the winding, thus winding said yarn into a composite pirn build.

4. Method according to claim 3, wherein said yarn is nylon monofilament yarn.

5. Method according to claim 4, wherein the number of traverse strokes per cycle is between 2 and 5.

References Cited UNITED STATES PATENTS 2,749,055 6/1956 Bauer 242-26.2

2,764,363 9/1956 Stammwitz 24226.2

FOREIGN PATENTS 1,221,167 1/1960 France.

STANLEY N. GILREATH, Primary Examiner. 

